Cardiac catheterization (kath-uh-tur-ih-ZAY-shun) is a procedure used to diagnose and treat cardiovascular conditions. During cardiac catheterization, a long thin tube called a catheter is inserted in an artery or vein in your groin, neck or arm and threaded through your blood vessels to your heart. Using this catheter, doctors can then do diagnostic tests as part of a cardiac catheterization. Some heart disease treatments, such as coronary angioplasty, also are done using cardiac catheterization.

Usually, you'll be awake during cardiac catheterization, but given medications to help you relax. Recovery time for a cardiac catheterization is quick, and there's a low risk of complications.

Cardiac catheterization is done to see if you have a heart problem, or as a part of a procedure to correct a heart problem your doctor already knows about.

If you're having cardiac catheterization as a test for heart disease, your doctor can:

Measure pressure and oxygen levels in different parts of your heart (hemodynamic assessment)

Check the pumping function of your heart (right or left ventriculogram)

Take a sample of tissue from your heart (biopsy)

Diagnose heart defects present from birth (congenital heart defects)

Look for problems with your heart valves

Cardiac catheterization is also used as part of some procedures to treat heart disease. These procedures include:

Angioplasty with or without stent placement. Angioplasty involves temporarily inserting and expanding a tiny balloon at the site of your blockage to help widen a narrowed artery. Angioplasty is usually combined with implantation of a small metal coil called a stent in the clogged artery to help prop it open and decrease the chance of it narrowing again (restenosis).

Closure of holes in the heart and fixing other congenital defects. Some congenital heart defects involving holes in the heart can be treated by threading a catheter to the hole to close it, almost like a plug, instead of having open-heart surgery. Narrow areas of blood vessels, such as coarctation of the aorta, can be opened up by a balloon. After that, a stent is usually placed to keep the blood vessel open.

Repair or replace heart valves. Using cardiac catheterization, doctors can sometimes repair or replace a leaking or narrowed heart valve. Sometimes, doctors will use catheterization to fix a leaking replacement valve.

Balloon valvuloplasty. This procedure can open narrowed heart valves by threading a balloon-tipped catheter to the part of your heart valve that's narrowed and inflating it.

Heart arrhythmia treatment (ablation). Ablation is a procedure used to treat heart rhythm problems. Radiofrequency energy (heat), a laser or nitrous oxide (extreme cold) can be applied to abnormal heart tissue through the tip of a catheter. This is done to reroute electrical signals or destroy (ablate) areas that are causing the heart rhythm disorder.

Closing off part of your heart to prevent blood clots. In addition to closing holes in the heart, cardiac catheterization can also be used to close off the part of the upper chamber of the heart called the left atrial appendage. This area of the heart is prone to developing blood clots during irregular heart rhythms, such as atrial fibrillation. Closing it off is an alternative to taking blood thinners.

As with most procedures done on your heart and blood vessels, cardiac catheterization has some risks. Major complications are rare, though.

Risks of cardiac catheterization are:

Bruising

Bleeding

Heart attack

Stroke

Damage to the artery where the catheter was inserted that may require additional attention (pseudoaneurysm)

Irregular heart rhythms (arrhythmias)

Allergic reactions to the dye or medication

Tearing the tissue of your heart or artery

Kidney damage

Infection

Blood clots

If you are either pregnant or planning to become pregnant, tell your doctor before having cardiac catheterization performed.

Cardiac catheterization is usually performed in the hospital. The test requires some preparations. To prepare for your test:

Don't eat or drink anything for at least 6 hours before your test, or as directed by your doctor. Having food or drink in your stomach can increase your risk of complications from anesthesia. Ask your doctor or nurse if you should take your medications with a small amount of water. If you have diabetes, ask for instructions about diabetes medications and insulin. You will usually be able to have something to eat and drink soon after your test.

Take all your medications and supplements with you to the test. It's best if you take the original bottles so that your doctor will know the exact dose you take.

Try to relax. People who are having a cardiac catheterization may feel anxious or nervous. You'll be given medications to help you relax. It's possible that the test will reveal that you need a procedure such as angioplasty right away, or that you could have a side effect from the medication given to you during the catheterization. Being nervous may cause your heart to beat more quickly or irregularly and may complicate the procedure.

Once you have checked in for your catheterization, you'll have your blood pressure and pulse checked. You'll be asked to use the toilet to empty your bladder. You'll be asked to remove dentures and may need to remove jewelry, especially necklaces that could interfere with pictures of your heart. You'll wait in a pre-operating room until it's time for your procedure — you can often have someone wait there with you.

Cardiac catheterization is done in a special operating room that has special X-ray and imaging machines that normal operating rooms don't have.

Cardiac catheterization is usually performed while you're awake, but sedated. An IV line will be inserted in your hand or arm, and will be used to give you any additional medications you might need during your procedure. You will also have monitors (electrodes) placed on your chest to check your heartbeat during the test.

Just before the procedure, a nurse or technician may shave the hair from the site where the catheter will be inserted. Before the catheter is inserted in your artery, you'll be given a shot of an anesthetic to numb the area. You may feel a quick, stinging pain before the numbness sets in.

After you feel numb, the catheter will be inserted. A small cut is made, usually in your leg, to access an artery. A plastic sheath will be inserted in the cut to allow your doctor to insert the catheter.

What happens next depends on why you're having a cardiac catheterization. These are some of the common uses for cardiac catheterization:

Coronary angiogram. If you're having this test to check for blockages in the arteries leading to your heart, a dye will be injected through the catheter, and X-ray images of your heart arteries will be taken. In a coronary angiogram, the catheter is usually first placed in the artery in your groin or wrist.

Right heart catheterization. This procedure checks the pressure and blood flow in the right side of your heart. For this procedure, the catheter is inserted in the vein in your neck or groin. The catheter has special sensors in it to measure the pressure and blood flow in your heart.

Heart biopsy. If your doctor is taking a sample of heart tissue (biopsy), the catheter will usually be placed in the vein in your neck. A catheter with a small, jaw-like tip is used to obtain a small sample of tissue from your heart. You may feel pressure as this catheter is being used, but you likely won't feel the actual tissue being snipped.

Balloon angioplasty, with or without stenting. This procedure is used to open a narrowed artery in or near your heart. The catheter will likely be inserted in the artery in your groin for this procedure. A long, flexible catheter will be threaded through your arteries to the narrowed artery. Then, a smaller balloon catheter will be led through the flexible catheter and inflated at the narrowed area to open it. In many cases, your doctor will also place a mesh coil called a stent at the narrowed portion to help keep the artery open.

Repair of heart defects. If your doctor is closing a hole in your heart, such as an atrial septal defect or patent foramen ovale, you will probably have catheters inserted in both the arteries and veins of the groin and neck. A device is then inserted into your heart to close the hole.

Balloon valvuloplasty. This procedure is done to open up narrowed heart valves. The placement of your catheters will depend on which valve problem you have. A catheter is threaded across the valve. A balloon is then blown up to make the valve open more easily. You may feel pressure as the catheters are inserted into your body, but you shouldn't feel discomfort from the balloon treatment itself.

Valve replacement. This procedure is similar to ballon valvuloplasty, except that an artificial valve will be implanted in your heart to replace a leaky or narrowed heart valve.

Heart ablation. In this procedure, you'll usually have multiple catheters placed in the arteries and veins of the groin or neck so that radiofrequency energy can be directed to the part of your heart causing abnormal heartbeats.

Although you'll be sedated, you'll be awake during the procedure so that you can follow instructions. Throughout the procedure you may be asked to take deep breaths, hold your breath, cough or place your arms in various positions. Your table may be tilted at times, but you'll have a safety strap on to keep you on the table.

Threading the catheter shouldn't be painful, and you won't feel it moving through your body. Tell your health care team if you have any discomfort.

After the procedure

It usually takes several hours to recover from a cardiac catheterization. After your procedure is finished, you'll be taken to a recovery room while the anesthesia wears off. This usually takes about an hour. The plastic sheath inserted in your groin, neck or arm will be removed soon after the procedure unless you need to continue on blood-thinning medication.

After you leave the recovery room, you'll go to a regular hospital or outpatient room. After your catheter is removed, the technician or nurse who has removed your sheath will apply pressure to the insertion sites. You'll need to lie flat for several hours after the procedure to avoid serious bleeding and to allow the artery to heal.

You'll be able to eat and drink after the procedure. The length of your stay in the hospital will depend on your condition. You may be able to go home the same day as your catheterization, or you may need to stay overnight or longer if you have an additional procedure, such as angioplasty and stent placement.

If you're having cardiac catheterization as a test, your doctor should explain the results to you. If you've had a coronary angiogram, your results could indicate that you need angioplasty or a stent, or a more major open-heart surgery called coronary bypass surgery. In some cases, your angiogram may show that angioplasty would likely be an effective treatment to open a narrowed artery. If your doctor finds this, he or she may perform angioplasty with or without a stent placement right away so that you won't need to have another cardiac catheterization. Your doctor should discuss whether this is a possibility before the procedure begins.

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